This invention relates to a sewing machine equipped with a sub-table device for converting the sewing machine from a free arm type to a flat bed type, and vice versa.
A sewing machine is known which is adapted for sewing a flat sheet-like work piece or material, or for sewing a tubular work piece. Coupled with the fact that such a sewing machine has a frame of a peculiar construction, difficulty has been experienced in the procedure for converting the sewing machine into a free arm type. Furthermore, the sewing machine is very costly to manufacture. Upon converting such a sewing machine into a flat bed type, the work supporting surface substantially continuous with that of the free arm is stretched rearwards rather than frontwards of the free arm, resulting in the inaccuracy in guidance and shifting of a work piece.